ML19210E448
| ML19210E448 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 11/16/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Tallman W PUBLIC SERVICE CO. OF NEW HAMPSHIRE |
| References | |
| NUDOCS 7912050058 | |
| Download: ML19210E448 (1) | |
Text
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Docket Nos. 50-443 NOV 161979 50-444 Public Service Company of New Hampshire ATTN:
Mr. W. C. Tallman President 1000 Elm Street Manchester, New Hampshire 03105 Gentlemen:
The enclosed IE Circular No. 79-22, " Stroke Times for Power Operated Relief Valves," is forwarded to you for information.
No written response is required.
Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely, e
W Boyce H. Grier Director
Enclosures:
1.
IE Circular No. 79-22 2.
List of Recently Issued Circulars CONTACT:
D. L. Caphton (215-337-5263) cc w/encls:
John D. Haseltine, Project Manager 1500 291 m eoso o SF
A ENCLOSURE 1 SSINS:
6830 Accession No.:
7908220142 UNITED STATES NUCLEAR REGULATORY COMMISSION
]O D 0 Of[B $ W gL OFFICE OF INSPECTION AND ENFORCEMENT U1 1
2 WASHINGTON, D. C.
20555 IE Circular No. 79-22 Date:
November 16, 1979 Page 1 of 1 STROKE TIMES FOR POWER OPERATED RELIEF VALVES Description of Cire~istances:
Most PWRs utilize power-operated relief valves (PORVs) to prevent overpressuriza-tion of the reactor coolant system when the reactor is at low temperature.
On April 13, during a pressure transient at Robinson 2, the PORVs did not function as rapidly as intended.
The estimated stroke time for the PORVs was three to five seconds whereas the intended stroke time is two seconds.
As a result, the pressure transient did approach a pressure limit which is based on nil ductility considerations.
Prior to April 13, the PORVs had not been used or exercised since February, 1978, when they had been repacked and stroked.
Although the valve stems were scored at that time, stroke times were satisfactory.
The licensc-e and the valve manufacturer believe that the scored stems and the 14-month interval without exercise resulted in poor performance of the PORVs.
Recommended Actions for Licensees' Consideration:
All holders of PWR operating licenses or construction permits should be aware of the potential problem of the type discussed above.
Because of the generic implications in this matter, it is recommended that both licensees of operating facilities and holders of construction permits conduct a review to determine if periodic serveillance of PORVs is necessary to assure that the PORVs will perform as intended.
No written response to this Circular is required.
If you require aduit.ional information regarding these matters, contact the Director of the appropriate NRC Regional Office.
1500 292
A ENCLOSURE 2 IE Circular No. 79-22 Date:
November 16, 1979 Page 1 of 1 RECENTLY ISSUED CIRCULARS Circular Subject First Date Issued To No.
of Issue 79-15 Bursting of High Pres-8/8/79 All Materials Priority sure Hose and Malfunc-I, Fuel Cycle and Opera-tion of Relief Valve "0"
ting Power Reactor Ring in Certain Self-Licensees Contained Breathing Apparatus
/9-16 Excessive Radiation 8/16/79 All Radiography Exposures to Members Licensees Of The General Public And A Radiographer 79-17 Contact Problem in 8/14/79 All Power Reactor SB-12 Switches on Licensees with an OL General Electric or CP Metalclad Circuit Breakers 79-18 Proper Installation of 9/10/79 All Power Reactor Target Rock Safety-Licensees with an OL Relief Valves or CP 79-19 Loose Locking Devices 9/13/79 All Power Reactor Licensees on Ingersoll-Rand Pumps with an OL or CD 79-20 Failure of GTE Sylvania 9/24/79 All Power Reactor Licensees Relay, Type PM Bulletin with an OL or CP 7305, Catalog SU12-11-AC with a 120V AC Coil 79-21 Prevention of Unplanned 10/19/79 All Pcwer Reactor Licensees Releases of Radioactivity with an OL or CP 1500 293